Synthesis and characterization of novel drug delivery nanoparticles based on polyzwitterionic copolymers

Copolymer (vinyl acetate (VA)-co-3-dimethyl(methacryloyloxyethyl)ammonium propane sulfonate (DMAPS)) nanoparticles have been synthesized by radical copolymerization in water. It was established that the variation of the initial monomer feed (DMAPS concentration was 10 mol% (copolymer 1) and 90 mol% (copolymer 2)) changes the copolymerization type, nanoparticles morphology, self-organization and size distribution. The shape, average diameter, size distribution and zeta potential of the copolymer nanoparticles are determined by atomic force microscopy (AFM), dynamic light scattering and zeta potential data, respectively. While the copolymer 1 nanoparticles are solid with spherical shape, average diameter 276 nm and zeta potential −25.2 mV, the copolymer 2 nanoparticles have bean-like shapes with an average diameter 49.3 nm and zeta potential −4.4 mV and contain many domains with different density. For the first time the AFM images of the copolymer 2 nanoparticles presented the unique self-organization of the dipole–dipole clusters of DMAPS units. The results indicated that the obtained copolymer nanoparticles with specific structure could be used as drug delivery systems.